1. Field of Invention
Embodiments of the invention relate generally, but are not limited to, cannula systems and methods of using a cannula with, for example, ventricular assist devices.
2. Discussion of Related Art
The use of a ventricular assist device (VAD) in patients suffering from damaged heart tissue or heart failure is known. A ventricular assist device may be used as a permanent solution for a patient, or may be used as a short-term solution while a patient is waiting for a heart transplant. VAD's may also be used to provide damaged heart muscle with the opportunity for rest to increase the probability of healing of the heart muscle, after which the VAD may be removed. Typically, a VAD is used to assist the left ventricle of the heart by drawing blood from the left ventricle, and pumping blood into the aorta.
FIG. 1 provides a diagram of a typical ventricular assist device 10 coupled to the heart 12 and the aorta 14 of a patient. The VAD 10 is coupled to the ventricle 13 of the heart using an inflow cannula 16 and is coupled to the aorta using an outflow cannula 18. VAD devices like that shown in FIG. 1 are available from ABIOMED, Inc. of Danvers, Mass., under the trade names BVS® 5000 Bi-Ventricular Support System and AB5000™ Circulatory Support System.
Typically, an inflow cannula is coupled to the heart tissue using purse string sutures in a well-known manner. When used properly, such purse string sutures provide an effective seal for the cannula to the heart, however, the sutures can loosen over time, require skill to install, and typically require opening of the chest cavity for installation and removal.